The Role of Capsule Endoscopy in Patients with Obscure Gastrointestinal Bleeding

Obscure gastrointestinal bleeding (OGIB) accounts for 5% of all gastrointestinal (GI) bleeding cases and is often caused by small bowel lesions. Capsule endoscopy (CE), which allows non-invasive visualization of the small bowel mucosa, has revolutionized the evaluation of OGIB. CE is preferred by both patients and physicians mainly because of its non-invasiveness, and is widely used as the first-line diagnostic modality for OGIB. The diagnostic yield of CE in OGIB has been reported to be in the range of 32% to 83%. Although no direct comparison has been made, a meta-analysis showed similar diagnostic yields between CE and double-balloon enteroscopy (DBE) for OGIB. However, CE could enhance the yield of subsequent DBE and serve as a guide for optimizing the insertion route for DBE. Even after negative CE, selected patients could benefit from second-look CE for OGIB. In terms of outcomes, a favorable clinical impact after CE has been reported in several studies. However, observations indicate that CE might not influence clinical outcomes directly, but rather play a role in selecting patients with OGIB who are likely to benefit from subsequent evaluation and intervention.